This invention has to do with a pick and place machine which transfers a production part from a loading station to a delivery station. It is especially concerned with a pick and place machine operating by a single actuator means that provides two directions of travel. Usually two horizontal directions of travel will be contemplated, although it is possible to have both a horizontal and vertical direction of travel depending on the orientation of the pick and place machine.
In the automation and production lines, it has become a standard practice for mechanisms to surround a production part, grip the part, and transfer it from one work station to another so that further processing of the production part may take place. The efficiency of the production line ideally requires that the transfer of the part from one production process to another be minimized. Toward this goal, devices known as pick and place machines are coming into existence so as to move the production part a very short distance from one location to another.
The pick and place machines require a moving member and a gripping member that may automatically extend so that it surrounds the part and then grips the part. Once the part has been engaged, the moving member is then retracted so that the part is taken out of its production environment. When the part has been removed from production environment sufficiently so that it may be moved without interference with the production line, a different motion must be applied to the part, usually a horizontal motion, to move it from one location to another. When the part has arrived at the new location, the moving member must then extend in a horizontal or vertical direction to place the part in its new location, at which point the grippers release the part and the moving member is retracted.
The actuation or actuators of the pick and place machines are usually comprised of air cylinders or fluidized cylinders, although electrical actuators may also be used. In general, the actuators are unidirectional in that they reciprocally extend and retract in a linear fashion upon energization. There are pick and place machines on the market today that use multiple linear actuators, one for each direction of travel that may be required for the pick and place carriage. In the usual case, a first reciprocal linear horizontal motion is required on the gripper arm, and a separate air cylinder provides that reciprocal motion. The pick and place machine requires a second direction of travel, usually at 90 degrees to the first direction of travel, and a second linear air cylinder is supplied to provide reciprocal motion in that direction.
Other devices have been suggested that utilize the single actuator. Such a device is illustrated in U.S. Pat. No. 4,095,691 to James P. O'Neil.
The goal of any pick and place machine is to make its operation as simple as possible while also maximizing the repeatability of its operation. Simple and efficient machines are almost always achieved when the complexity of the machine is reduced and the interaction between the parts is simplified as much as possible. Reliability increases in the direct proportion to the reduction of parts and interactions on the pick and place machines. In addition to the foregoing factors, the precision and tolerances of the pick and place machines are important and sometimes critical to the placement of the part from one location to another during production. For this reason, the preciseness of the location of the part of the pick up and delivery points is also important in these machines along with their reliability.